Validity between signs and symptoms of sleep bruxism against a validated portable electromyographic device.

Background: Sleep bruxism is a major research area in dentistry today and needs valid clinical means of diagnosis against valid instrumental methods. Purpose: To assess the validity of the most commonly reported sleep bruxism (SB) signs and symptoms in the literature against a polysomnography (PSG) validated portable electromyographic (EMG) device (BiteStrip®). Material and Methods: Fifty young adults (40 women & 10 men, 18-30 years old) volunteered for the sequential and simultaneous administration of the SB signs and symptoms questionnaire versus the BiteStrip®. The SB signs and symptoms questionnaire was comprised of 19 items divided in 5 areas: a) Area 1: self-awareness of tooth grinding, clenching, and/or tooth sounds/noises, b) Area 2: headaches and/or facial pain, c) Area 3: muscle fatigue and/or hypertrophy, d) Area 4: clicking, crepitation and/or locking in the TMJ, and e) Area 5: tooth sensitivity, tooth wear/breaking, and/or cheek/tongue indentations. A cross-tabulation between the dichotomic test results (positive = 1, negative = 0) between the all five SB areas separately using quartiles (positive test result=75th percentile or higher, negative test result=50th percentile or lower) versus a positive test result of the BiteStrip® (score=1 or higher) was performed. Results: Area 1 presented the highest sensitivity for SB screening (80.0%), but with low specificity (51.4%), diagnosing most SB cases, but with a high number of false positives. All other four areas had low sensitivity (range=37.9% to 58.6%) and screening capacity and are only useful if Area 1 is positive. Conclusions: Commonly reported SB signs and symptoms are not valid diagnostic measurements and can only be used as a screening method for either 'possible' or 'probable' SB diagnosis.